In recent years, various adhesion-type percutaneously absorbable preparations for continuous administration of a drug from the skin surface have been developed and become commercially available. The technical direction they pursue from now on will be toward maintenance of superior drug absorbability while suppressing skin irritation that occurs upon adhesion and peeling off of the preparation.
However, too much emphasis on the suppression of physical stimulation upon peeling off, which leads to unnecessarily reduction of the adhesive force, undesirably impairs adhesiveness of adhesive preparation. Particularly, in the case of a percutaneously absorbable adhesive preparation containing a drug, falling off of the preparation during the effective period becomes a serious defect that loses effectiveness as a pharmaceutical product.
To suppress physical irritation upon peeling off, for example, a method ensuring an adequate adhesive force and suppressing damages on the keratin layer upon peeling off of adhesive preparation by constituting a special gel structure (JP-B-2700835, JP-B-2970772), a method using a highly permeable support and a special adhesive (JP-B-2524190), a method using an adhesive layer designed to be re-adherable, wherein the adhesion site is changed during the effective period (U.S. Pat. No. 6,348,210) and the like have been disclosed. However, none has ever existed which takes note of changing the peelability between the initial stage of adhesion and at the time of peeling off, thereby to maintain fine drug absorbability and suppress skin irritation caused by adhesion and peeling off.